i've used 98se as a main os for some years and yeah, it's less stable than xp and stuff but at least it's not all bloated and full of stupid shit and background processes that i'll never ever use... XP is thought more for newer computers that have the brawn to run needless stuff in the background
i used XP for a while in another partition but i ended up deleting it and using the partition for storage anyway
and also i tried some linux distributions... first i used Turbolinux 6 which came in a magazine, it wasn't bad but it was still very untidy... lots of broken stuff that you needed to correct, etc
then i jumped to Redhat 7.2 (big jump hehe) and i was blown off my ass... everything worked so absolutely right, it was great... the bad thing is that it's too big, 1.5gig for an os installation... given, it came with all kinds of other shit, but i'd rather choose what i have on my disk
so now for linux i use Linux From Scratch, which more than a distrubution is a "recipe" of which individual packages you need to download and compile, etc to make a generic Linux installation from 0, using an already existing Linux installation to build it up
it's very hefty and you have to sit through a few hours of compiling and stuff, but in the end it teaches you a lot and you know exactly what you have and where you have it, etc
LFS rules
www.linuxfromscratch.org